Duktape – embeddable JavaScript engine with a focus on portability and compact footprint

This sounds like something that would benefit mainstream browsers, for cold spots:

https://github.com/svaarala/duktape/blob/master/doc/low-memo...

"Notes on pointer compression

Pointer compression can be applied throughout (where it matters) for three pointer types:

* Compressed 16-bit Duktape heap pointers, assuming Duktape heap pointers can fit into 16 bits, e.g. max 256kB memory pool with 4-byte alignment

* Compressed 16-bit function pointers, assuming C function pointers can fit into 16 bits

* Compressed 16-bit non-Duktape-heap data pointers, assuming C data pointers can fit into 16 bits "